The invention relates to supports for seats, especially for seats of motor vehicles. More particularly, the invention relates to improvements in supports of the type wherein a fixed first rail (hereinafter called guide or track) movably supports and guides a second rail which is affixed to or forms part of a movable seat. Still more particularly, the invention relates to improvements in supports which are normally used in pairs, one along each side of the body-supporting portion of an adjustable seat.
German Pat. No. 32 21 959 discloses a support wherein two spaced-apart walls are connected to each other to resemble a substantially box-shaped body which serves as a supporting rail and is movable along its track. The walls of the rail have a semicircular cross-sectional outline and constitute elongated shells provided with flange-like upper portions which are spot-welded to each other and serve to carry the seat. The walls are made of sheet steel and the thus formed supporting rail is put to use when the configuration of the adjacent rail-shaped portion of the seat is rather complex so that it cannot be readily made of profiled rolled steel. The rail-shaped portion is called upon to stand pronounced stresses in the event of an accident (it being assumed here that the seat which is mounted on a pair of rails each composed of two shell-shaped sections is the seat in a motor vehicle); therefore, the shells of each supporting rail must be made of relatively thick sheet steel in order to ensure that the supporting rails will exhibit the required stability. This contributes to the bulk and weight of the supporting rails and of the combinations of supporting rails and their tracks. On the other hand, the manufacturers of motor vehicles attempt to reduce the weight of component parts to a minimum and to use lightweight materials whenever the use of such materials does not affect the stability, reliability and safety of the vehicles.